This invention relates to catoptric systems for use in microfilm viewers, or motion picture projectors, and more particularly to a catoptric projection system in which a projection lens, a cylindrical lens and a spherical convex mirror are arranged to project the film onto the screen at an increased magnification while compensating for the astigmatism introduced by the mirror.
Catoptric projection apparatus of the conventional type utilize plane mirrors in projecting films onto screens at increased magnifications. With such an arrangement, it is impossible to achieve a much-desired increase in the magnification of the projected image without involving any great increase either in the refractive power of the projection lens or in the optical path length between the film plane and the screen.